1. Field of the Invention
The present invention relates to a semiconductor device and manufacturing method therefor, a circuit board, and electronic equipment.
2. Description of the Related Art
Semiconductor devices have recently been developed in which a plurality of semiconductor chips are formed into a stack. In many cases, electrical connections are intended to be done by bonding wires or leads to electrodes of the semiconductor chips, but the limit of miniaturization has been reached for the provision of wires and similar components. Electrical connections have also been developed such that a through-hole is formed in a semiconductor chip, then solder is poured into the through-hole. However, voids occur when solder is poured into tiny through-holes, making it difficult to guarantee reliable electrical connections
The present invention was devised to solve the above problem and has as an objective thereof the provision of a semiconductor device and manufacturing method therefor, a circuit board, and electronic equipment that enable simplification by highly reliable electrical connections.
(1) A method of manufacturing a semiconductor device in accordance with one aspect of the present invention comprises:
a first step of forming a through-hole in a semiconductor element having an electrode; and
a second step of forming a conductive layer in a region including an inner side of the through-hole.
This aspect of the present invention enables an electrical connection between one surface of the semiconductor element and the other surface thereof, by the formation of the conductive layer in the through-hole. By simply forming this conductive layer without having to fill the through-hole with a molten material, therefore, it becomes possible to ensure highly reliable electrical connections with no problems concerning the formation of voids.
(2) With this method of manufacturing a semiconductor device,
a hole may be formed in the electrode to overlap with the through-hole,
the conductive layer may be formed on at least part of the electrode.
This makes it possible to form the conductive layer having an electrical connection with the electrode.
(3) With this method of manufacturing a semiconductor device,
the through-hole may be formed to a shape having an aperture edge portion and an intermediate portion of which width is larger than a width of the aperture edge portion.
This makes it easy to form the conductive layer, because the intermediate portion of the through-hole is of a larger width. It should be noted that xe2x80x9cwidthxe2x80x9d means a diameter if the through-hole is a round hole or a length of one side if the through-hole is a rectangular hole.
(4) With this method of manufacturing a semiconductor device,
all portions of the intermediate portion may be formed at substantially the same width, and
the through-hole may be further formed to a shape having a tapered portion connecting the aperture edge portion with the intermediate portion.
Since this ensures that the width of the intermediate portion is substantially uniform over all portions thereof, stresses are made uniform and it is possible to suppress any drop in the strength of the semiconductor element due to the formation of the through-hole
(5) With this method of manufacturing a semiconductor device,
the through-hole may be formed in the first step by first forming a pinhole of a width smaller than a width of the through-hole, then expanding the pinhole.
This makes it possible to form the pinhole with less energy than that required for forming the through-hole, so that less energy is used for forming the through-hole by forming the pinhole.
(6) With this method of manufacturing a semiconductor device,
a cavity may be formed in the first step at a position at which the through-hole is to be formed, then the pinhole may be formed by positioning at the cavity.
Since the position at which the through-hole is formed can be confirmed by the cavity, it is possible to form the through-hole at an accurate position.
(7) With this method of manufacturing a semiconductor device,
the pinhole may be formed by a laser beam, then the pinhole may be enlarged by wet etching.
This makes it easy to form the through-hole. In addition, since the pinhole is enlarged by wet-etching, it is possible to form the through-hole with smooth inner surfaces, even if the inner surfaces of the pinhole formed by the laser beam is rough.
(8) With this method of manufacturing a semiconductor device, the method may further comprise a step of forming an electrical connection portion.
(9) With this method of manufacturing a semiconductor device,
the electrical connection portion may be formed as part of the conductive layer in the second step.
(10) With this method of manufacturing a semiconductor device, the method may further comprise a step of forming an insulation film on an inner surface of the through-hole, after the first step and before the second step, and
the conductive layer may be formed on the insulation film in the second step.
(11) With this method of manufacturing a semiconductor device,
the insulation film may be formed by chemical vapor deposition.
(12) With this method of manufacturing a semiconductor device,
the conductive layer may be formed by electroless plating.
It is particularly preferable that easy stirring of the plating liquid is enabled by making the shape of the intermediate portion of the through-hole expand to be larger.
(13) With this method of manufacturing a semiconductor device,
a catalyst may be exposed in at least a region in which the conductive layer is formed, electroless plating may be performed to extract a conductive material in the exposed region of the catalyst, and the conductive layer may be formed from the conductive material.
(14) With this method of manufacturing a semiconductor device,
the semiconductor element may be a semiconductor chip.
(15) With this method of manufacturing a semiconductor device,
the semiconductor element may be part of a semiconductor wafer.
(16) A method of manufacturing a semiconductor device in accordance with another aspect of the present invention further comprise a step of stacking semiconductor devices that were formed by the above described method, and electrically connecting together the conductive layer of each of upper and lower semiconductor devices.
A three-dimensional structure can be applied to this method of manufacturing a semiconductor device.
(17) The method of manufacturing a semiconductor device in this aspect may further comprise a step of cutting the semiconductor wafer into pieces.
(18) A semiconductor device in accordance with further aspect of the present invention is manufactured by the above-described method.
(19) A semiconductor device in accordance with still further aspect of the present invention comprises:
a semiconductor element having an electrode and in which a through-hole is formed; and
a conductive layer formed in a region including an inner side of the through-hole.
This aspect of the present invention enables an electrical connection between one surface of the semiconductor element and the other surface thereof, by the formation of the conductive layer in the through-hole. By simply forming this conductive layer without having to fill the through-hole with a molten material, therefore, it becomes possible to ensure highly reliable electrical connections with no problems concerning the formation of voids.
(20) With this semiconductor device,
a hole may be formed in the electrode to overlap with the through-hole,
the conductive layer may be formed on at least part of the electrode.
This forms the conductive layer in electrical contact with the electrode.
(21) With this semiconductor device,
the through-hole may be formed to a shape having an aperture edge portion and an intermediate portion of which width may be larger than a width of the aperture edge portion.
This makes it easy to form the conductive layer, because the intermediate portion of the through-hole is of a larger width. It should be noted that xe2x80x9cwidthxe2x80x9d means a diameter if the through-hole is a round hole or a length of one side if the through-hole is a rectangular hole.
(22) With this semiconductor device,
all portions of the intermediate portion may be formed at substantially the same width, and
the through-hole may be further formed to a shape having a tapered portion connecting the aperture edge portion with the intermediate portion.
Since this ensures that the width of the intermediate portion is substantially uniform over all portions thereof, stresses are made uniform and it is possible to suppress any drop in the strength of the semiconductor element due to the formation of the through-hole.
(23) With this semiconductor device,
a connection portion may be provided by part of the conductive layer.
(24) With this semiconductor device,
an insulation film may be further formed on an inner surface of the through-hole and the conductive layer may be formed on the insulation film.
(25) With this semiconductor device,
the semiconductor element may be a semiconductor chip.
(26) With this semiconductor device,
the semiconductor element may be part of a semiconductor wafer.
(27) In a semiconductor device in accordance with even further aspect of the present invention, the above described semiconductor device are stacked, and the conductive layer of each of upper and lower semiconductor devices are connected together electrically.
A three-dimensional structure can be applied to such a semiconductor device.
(28) A circuit board in accordance with yet further aspect of the present invention has a semiconductor device mounted thereon.
(29) Electronic equipment in accordance with more aspect of the present invention is provided with the above described semiconductor device.